In the said Cunningham patent, the surface unit comprises a spiralled metal tube having one closed end, and containing compacted refractary insulation and a helical resistor coil. The coil is insulated from the metal tube by the refractory insulation and is connected at one end to a central return conductor. The terminations for the coil and return conductor both extend from the end of the tube opposite the said closed end. The surfact unit is so constructed that in the event of a failure of the heating element, the failure will be in a passive manner.
Because the terminals for the coil and return conductor both extend from one end of the sheath, dielectric clearance between the two and the sheath presented a problem. My invention overcomes this problem and provides a sealed terminal connector that is adapted to be plugged into a receptacle of presently-used form, such as shown in U.S. Pat. No. 3,447,121, issued May 27, 1969, to G. E. Ammerman and D. M. Cunningham, and assigned to the same assignee as is the present application.